1. Field of the Invention
The present invention relates to a protective sheet peeling device and a protective sheet peeling method which peel-off and separate a protective sheet from a sheet at the time when the sheet, on whose one surface the protective sheet is superposed and which is removed together with the protective sheet, is conveyed and supplied to a subsequent process.
2. Description of the Related Art
A technique (printing plate exposing device) has come to be developed which, by using a printing plate precursor (hereinafter called “printing plate”) in which a recording layer (photosensitive layer) is provided on a support (e.g., a PS plate, a thermal plate, a photopolymer plate, or the like), records an image directly by a laser beam or the like onto the photosensitive layer of the printing plate. With such a technique, it is possible to quickly record an image onto a printing plate.
Here, in an automatic printing plate exposing device using a technique of recording an image onto a printing plate, a large number of printing plates are stacked and accommodated within a cassette. The image forming surface of the printing plate is easily scratched. In order to protect the image forming surfaces, protective sheets (interleaf sheets) are superposed on the image forming surfaces of the printing plates. The printing plates and the protective sheets are successively stacked in layers and accommodated within the cassette. At the time when a printing plate is to be removed from the cassette, the uppermost printing plate among the plural printing plates stacked within the cassette is sucked by suction cups and separated from the other printing plates. That uppermost printing plate is singly removed (the printing plates are removed one-by-one), and while being inverted, is fed (conveyed and supplied) to a subsequent process (e.g., an exposure section) (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2000-247489).
When the printing plates are removed one-by-one from the cassette and conveyed and supplied to the subsequent process as described above, the protective sheet must of course be peeled off (separated) from the printing plate, such that only the printing plate is conveyed and supplied to the next process which is the exposure process or the like.
In this case, conventionally, for example, suction cups used exclusively for sucking the protective sheet were provided, and the protective sheet was sucked by these exclusive suction cups and peeled off (separated) from the printing plate. Or, a fan for sucking of the protective sheet was provided along the conveying path of the printing plate conveyed together with the protective sheet, and the protective sheet was sucked by the fan and separated from the printing plate.
However, in such conventional protective sheet peeling (separating) structures, in both cases, the structure is complex and the device becomes large. There is therefore room for improvement with regard to the points of ensuring the stability of and shortening the processing time for the peeling off of the protective sheet.